Different types of procedures for protection against jamming in a motor-driven locking system are known from the state of the art. In order to avoid a threat of persons or a damage of objects, such systems have to have a jamming protection. Therefore a jamming situation has to be noticed reliably.
To recognize a jamming situation usually a driving electromotor is controlled. If a specified jamming force reduces a motor engine speed of the drive, a jamming situation is detected and the drive direction of the motor is reversed. Thereby a reversion of the locking process is executed. Due to statutory provision the measurement of the jamming force takes place usually with spring rates of 10 N/mm, 20 N/mm and 65 N/mm. But in particular the hard spring rate of 65 N/mm has different requirements than the softer spring rates. Therefore two different algorithms are implemented usually in a memory, in order to detect a jamming situation at the sot and the hard spring rate.
But de facto it happens over and over that due to mechanic problems, particularly increased rubbing at transition points of the sun roof or the window, an engine speed course occurs at the drive, which corresponds a course of a jamming situation with the hard spring rate. Thereby the system is falsely reveres due to the mechanic problems, even though no jamming situation occurred. Even though modern locking systems provide an adaptation algorithm, in order to allow an automatic adaptation of stiffness during a locking process and to continue the locking process, the adaptation algorithm cannot react quickly enough at the hard spring rate. Thereby it is not possible to compensate the stiffness at this position with the present adaptation algorithm. Furthermore the familiar adaptation algorithms mostly save the necessary information only over several and support points along the entire of the locking system and detected over support points, so that certain inaccuracies occur.